Answer: C
Explanation: I'm not one hundred percent sure I know the context of this question, but biodiversity in an ecosystem means there's a wide variety of organisms, and a hotspot I assume would be an area that has an unusual amount of diversity.
Answer: High Frequency waves by method of compression bone conduction
Explanation: in this, vibration of the bones of the skull and sometimes, arguably soft tissues leads to the production of sounds. The outer and middle ear is bypassed in this method of sound production. Sound reaches the inner ear directly and its a process largely involved in designing hearing aids.
I am fairly sure the answer is B
D the amount of matter in the chair